National Geographic News: Pandas in the United States

Lower left: Hua Mei (bottom), pronounced 'hwa may', is the fifth giant panda born in the United States and the first at the San Diego Zoo. Shown as a young cub with her mother Bai Yun, who also resides at the zoo, Hua Mei will be four years old on August 21. Upper left: Hua Mei, Chinese for "China U.S.A.," celebrates her second birthday in 2001.

Right: Gao Gao, pronounced gow-gow and meaning "big big", is a wild-born adult male from China's Wolong Nature Reserve. Gao Gao arrived at the San Diego Zoo in January of 2003. He is not the father of Hua Mei. Her father, Shi Shi, was returned to China earlier this year.

Hua Mei's birth allowed keepers and researchers to study advance indicators of a giant panda pregnancy as well as compare behavioral, hormonal, and physiological changes in the female during pregnancy. San Diego's trio of pandas are being used to study communication, reproductive behavior, and infant behavior and development.